Shift lever assembly with park shift assist mechanism

ABSTRACT

A park shift assist mechanism of a shift lever assembly for a vehicle is provided. The park shift assist mechanism includes a pressing portion configured to apply a pressing force and a follower configured to cause rotation of a gear shift lever from a reverse position to a park position when the gear shift lever is positioned between the reverse position and the park position in response to the pressing force being applied to the follower.

This patent application is a continuation of U.S. patent applicationSer. No. 13/920,849, filed Jun. 18, 2013, which claims priority to U.S.Provisional Patent Application Ser. No. 61/661,089, filed Jun. 18, 2012,which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The following description relates to a column mounted transmission gearshift lever, and in particular, a column mounted transmission gear shiftlever having a mechanism to assist movement of the gear shift lever intoa park position.

Vehicles may include a column mounted transmission gear shift lever toshift between different gear positions of the transmissions. A columnmounted gear shift lever typically relies on an operator to manuallycomplete a shifting motion to actuate the transmission in to the desiredgear position.

A transmission may include a leaf spring mechanism within thetransmission to overcome frictional forces of the entire system if theoperator inadvertently does not complete shifting motion. If thefrictional forces are too high, there could be a misalignment betweenthe gear shift lever and the transmission.

Accordingly, it is desirable to provide a supplemental artificial feelmechanism which is more in sync with the transmission in order to reduceoccurrences of the misalignment described above. Further, it may be mostadvantageous to provide such a mechanism when the gear shift lever isreentering the park position.

SUMMARY OF THE INVENTION

According to an exemplary embodiment of the present invention, there isprovided a park shift assist mechanism of a shift lever assembly for avehicle. The park shift assist mechanism includes a pressing portionconfigured to apply a pressing force and a follower configured to causerotation of a gear shift lever from a reverse position to a parkposition when the gear shift lever is positioned between the reverseposition and the park position in response to the pressing force beingapplied to the follower.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 illustrates a park shift assist mechanism according to anexemplary embodiment of the present invention;

FIG. 2 illustrates the park shift assist mechanism according to thefirst exemplary embodiment of the present invention;

FIG. 3 illustrates the park shift assist mechanism according to thefirst exemplary embodiment of the present invention;

FIG. 4 illustrates the park shift assist mechanism according to thefirst exemplary embodiment of the present invention;

FIG. 5 illustrates the park shift assist mechanism according to thefirst exemplary embodiment of the present invention;

FIG. 6 illustrates the park shift assist mechanism according to thefirst exemplary embodiment of the present invention;

FIG. 7 illustrates a park shift assist mechanism according to a secondexemplary embodiment of the present invention;

FIG. 8 illustrates the park shift assist mechanism according to thesecond exemplary embodiment of the present invention;

FIG. 9 illustrates the park shift assist mechanism according to thesecond exemplary embodiment of the present invention;

FIG. 10 illustrates the park shift assist mechanism according to thesecond exemplary embodiment of the present invention;

FIG. 11 illustrates a park shift assist mechanism according to a thirdexemplary embodiment of the present invention;

FIG. 12 illustrates the park shift assist mechanism according to thethird exemplary embodiment of the present invention;

FIG. 13 illustrates the park shift assist mechanism according to thethird exemplary embodiment of the present invention;

FIG. 14 illustrates the park shift assist mechanism according to thethird exemplary embodiment of the present invention;

FIG. 15 illustrates the park shift assist mechanism according to thethird exemplary embodiment of the present invention; and

FIG. 16 illustrates the park shift assist mechanism according to thethird exemplary embodiment of the present invention.

DETAILED DESCRIPTION

Referring now to the Figures, where the invention will be described withreference to specific embodiments, without limiting same, exemplaryembodiments of park shift assist mechanisms 10 are provided. Exemplarypark shift assist mechanisms 10 may be configured to maintain alignmentbetween a gear shift lever 23 and a vehicle transmission (not shown).

In an exemplary embodiment, a gear shift assembly may be mounted to asteering column of a vehicle. The gear shift assembly includes a gearshift lever 23 that is movable between a plurality of shift leverpositions, each corresponding to a unique gear position (i.e., operatingmode) of the vehicle transmission. The gear shift lever 23 and gearshift assembly are operably connected to the vehicle transmission so asto facilitate shifting between operating modes of the transmission(e.g., from one gear position to another gear position or from a drivingmode, in which a driving gear is engaged to a vehicle power-plant, to aparking mode, in which the transmission is disengaged from thepowerplant) according to a position or a movement of the gear shiftlever 23.

FIGS. 1-6 illustrate a park shift assist mechanism 10 according to anexemplary embodiment of the present invention. With reference to FIGS. 1and 2, the park shift assist mechanism 10 includes a pressing portion.The pressing portion is configured to apply a pressing force. In anexemplary embodiment, the pressing portion includes biasing means suchas a spring-loaded bearing follower 12 comprising a spring 14 and aroller ball 16. The park shift assist mechanism 10 also includes afollower in the form of a bearing ramp 18, in which the roller ball 16is positioned. The bearing ramp 18 is configured to cause rotation of agear shift lever 23 in response to the pressing force being applied tothe bearing ramp 18.

The spring loaded bearing follower 12 is positioned in a support bracket20 and the bearing ramp 18 is positioned on a gear clevis 22. The gearclevis 22 is operably connected to a gear shift lever 23 and movabletherewith. The roller ball 16 is urged toward the bearing ramp 18 andmoves within the ramp as the gear clevis 22 is rotated between differentpositions corresponding to different gears of the transmission.

With reference to FIGS. 3 and 4, the bearing ramp 18 includes a firstportion 24 and a second portion 26 separated from the first portion 24by a detent finger 28. In an exemplary embodiment, the first portion 24corresponds to a park position of the gear shift lever 23. The secondportion 26 corresponds to a plurality of other positions of the gearshift lever 23. The detent finger 28 separates the park position from areverse position in the second portion 26.

The detent finger 28 includes a first ramp 30 that extends into thefirst portion 24 and a second ramp 32 that extends into the secondportion 26. The first ramp 30 extends from a tip region 40 of the detentfinger 28 towards the first portion 24. The second ramp 32 extends fromthe tip region 40 of the detent finger 28 towards the second portion 26.The tip region 40 has a tip region radius of curvature, t_(R), and theroller ball 16 has a roller ball radius of curvature, b, that is lessthan the tip region radius of curvature, t_(R). In operation, if anoperator only moves the gear shift lever 23 partially to the parkposition, such that the gear shift lever 23 is between the park positionand the reverse position, the spring loaded bearing follower 12 acts topositively position the gear shift lever 23 in either the park positionor the reverse position.

For example, and with further reference to FIG. 3, if the gear shiftlever 23 is positioned between the park position and the reverseposition as shown in FIG. 4, the roller ball 16 is positioned proximateto the detent finger 28 between the first portion 24 and the secondportion 26 of the bearing ramp 18. The roller ball 16 is urged againstthe detent finger 28 by the spring 14.

The roller ball 16, when urged against the detent finger 28, actsagainst either the first ramp 30 or the second ramp 32 to positivelyposition the gear shift lever 23 in either park position or the reverseposition. The spring 14 supplies to the pressing force to the rollerball 16.

FIG. 4 shows the gear clevis 22 and gear shift lever 23 together with agear position detent 34. The gear position detent 34 includes aplurality of detent positions corresponding to various gears of thevehicle transmission. For example, the gear position detent 34 includesa park position detent 36 and a reverse position detent 38. The springloaded bearing follower 12 is configured to urge the gear shift lever 23to either the park position detent 36 or reverse position detent 38 ifthe gear shift lever 23 is positioned between the park position andreverse position.

Thus, in this embodiment, the spring loaded bearing follower 12 is fixedagainst movement in a shifting direction, i.e., a direction of rotationof the gear clevis 22 and/or gear shift lever 23 to shift between gearsof the transmission, and the bearing ramp 18 moves relative to thespring loaded bearing follower 12 in the shifting direction topositively position the gear shift lever 23.

FIGS. 5 and 6 show additional views of the park shift assist mechanism10. For example, FIG. 5 shows the spring loaded bearing follower 12 andFIG. 6 shows the bearing ramp 18 positioned on a shaft of the gear shiftlever 23.

It is understood that the bearing ramp 18 is not limited to beingpositioned on the gear clevis 22. Rather, the bearing ramp 18 may bepositioned on the gear shift lever 23 or on another feature that moveswith the gear clevis 22 or gear shift lever 23, such as a shaft oradapter. In addition, the gear clevis 22 may be formed integrally withthe gear shift lever 23 or separately therefrom.

FIGS. 7-10 illustrate a park shift assist mechanism 110 according to asecond exemplary embodiment of the present invention. The park shiftassist mechanism 110 includes a pressing portion in the form of a springloaded bearing follower 112 having a spring 114 and roller ball 116, anda follower in the form of a bearing ramp 118 similar to the park shiftassist mechanism 10 described above. The pressing portion is configuredto apply a pressing force and the bearing ramp 118 is configured tocause rotation of a gear shift lever 23 in response to the pressingforce being applied to the bearing ramp 118.

However, in this embodiment, the positions of the spring loaded bearingfollower 12 and bearing ramp 18 are reversed. That is, in this exemplaryembodiment, the spring loaded bearing follower 112 is positioned on thegear clevis 22 or gear shift lever 23, and the bearing ramp 118 isposition on the support bracket 20.

The park shift assist mechanism 110 of this embodiment operates in thesame manner as the park shift assist mechanism 10 described above tourge a gear shift lever 23 to either a park position or a reverseposition. For convenience, similar parts in this embodiment areidentified using the same reference numbers used above, except whereother reference numbers are specifically provided. In addition,description of similar parts may be omitted below for convenience.

FIG. 7 illustrates the park shift assist mechanism 110 including apressing portion in the form of a spring loaded bearing follower 112having a spring 114 and roller ball 116 mounted in a shaft of the gearclevis 22. The roller ball 116 is urged toward the bearing ramp 118 bythe spring 114.

FIGS. 8 and 9 illustrates the bearing ramp 118 formed in the supportbracket 20. The bearing ramp 118 is formed as a track in the supportbracket 20. The bearing ramp 118 includes a first portion 24 and asecond portion 26 separated by a detent finger 28. In an exemplaryembodiment, the first portion 24 corresponds to a park position of thegear shift lever 23 and the second portion 222 corresponds to aplurality of gear positions of the gear shift lever 23. The detentfinger 28 includes a first ramp 30 and second ramp 32.

In operation, the roller ball 116 is urged against the bearing ramp 118by spring 114. The pressing force is supplied by the spring 114. Asdescribed above, when the gear shift lever 23 is positioned between thepark position and the reverse position, the roller ball 116 is actsagainst the detent finger 28 and first ramp 30 or second ramp 32 topositively position the gear shift lever 23 in one of the park positionor the reverse position. Accordingly, the gear shift lever 23 may beproperly aligned with the gear of the vehicle transmission.

Thus, in this embodiment, the bearing ramp 118 is fixed against movementin the shifting direction, and the spring loaded bearing follower 112moves relative to the bearing ramp 118 in the shifting direction topositively position the gear shift lever 23.

FIG. 10 illustrates an alternative view of the spring loaded bearingfollower 112 including the spring 114 and the roller ball 116 inaccordance with an exemplary embodiment of the present invention.

FIGS. 11-16 illustrate a park shift assist mechanism 210 according to athird exemplary embodiment of the present invention. In this exemplaryembodiment, and with reference to FIGS. 11-13, the park shift assistmechanism 210 includes a pressing portion formed as an electronic parkassist solenoid 212. The park assist solenoid is configured to apply apressing force via an armature 214. The armature 214 is movable betweena plurality of positions corresponding to different gear positions of agear shift lever 23.

The park shift assist mechanism 210 also includes a follower in the formof a shift plate 216. In an exemplary embodiment the shift plate 216 isconfigured to cause rotation of the gear shift lever 23 in response tothe pressing force being applied to the shift plate 216. The shift plate216 is pivotable between a plurality of positions corresponding todifferent gear positions of the gear shift lever 23. The shift plate 216includes a connection pin 218 that is operable connected to one end ofthe armature 214 of the 214 of the electronic park assist solenoid 212.The shift plate 216 also includes a positioning groove 219. In anexemplary embodiment, the positioning groove 219 may include a firstportion 220 corresponding to a park position of the gear shift lever 23and a second portion 222 corresponding to a plurality of other gearpositions of the gear shift lever 23. A positioning pin 224 extendswithin the positioning groove 219. The positioning pin 224 may bepositioned at different locations along the positioning groove 219 dueto pivoting of the shift plate 216.

FIGS. 14-16 illustrate the armature 214 of the electronic park assistsolenoid 212 moving between different positions corresponding todifferent gear positions of the gear shift lever 23. The armature 214 isconnected to the shift plate 216 in such a way that pivoting of theshift plate 216 causes the armature 214 move, or alternatively, movementof the armature 214 causes the shift plate 216 to pivot. That is, thearmature 214 may apply a pressing force to the shift plate 216 to causethe shift plate 216 to pivot.

In an exemplary embodiment, the armature 214 is retracted as it movesfrom a position corresponding to a neutral gear position (FIG. 14) to aposition corresponding to a reverse gear position (FIG. 15). Thearmature 214 is further retracted as it moved from the positioncorresponding to the reverse gear position (FIG. 15) to a positioncorresponding to the park gear position (FIG. 16). As the armature 214moves between the park and reverse positions, a magnetic field assiststhe gear shift lever 23 into the park position. That is, a magneticfield may be used to assist the armature 214 moving toward the parkposition. In turn, the armature 214 may pivot on the shift plate 216toward the park position of the gear shift lever 23.

In an exemplary embodiment, the gear shift lever 23 may be operablyconnected to the shift plate 216, such that movement of the gear shiftlever 23 between different positions causes the shift plate 216 torotate.

The electronic park assist solenoid 212 may be operatively connected toa control unit (not shown). The control unit and/or the electronic parkassist solenoid 212 may be connected to at least one sensor to detectthe position of the gear shift lever 23. The sensor or sensors may bepositioned at any location where the position of the gear shift lever 23may be detected, and detect, for example, movement and position of thearmature 214, movement and position of the shift plate 216, and theposition of the positioning pin 224 in the positioning groove 219.Accordingly, the control unit may detect when the gear shift lever 23 isbetween the reverse position and the park position and activate themagnetic field to assist the gear shift lever 23 into the park position.Alternatively, the magnetic field may automatically be activated uponthe armature 214 reaching a predetermined position in the electronicpark assist solenoid 212.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description.

Having thus described the invention, it is claimed:
 1. A park shiftassist mechanism, comprising: a spring loaded bearing follower that ispositioned in a support bracket that is disposed adjacent to a gearclevis that is operably connected to a gear shift lever, the gear shiftlever being movable between a park position and a reverse position, thespring loaded bearing follower comprising a spring and a roller ballbiased towards a bearing ramp positioned on and extending into the gearclevis by the spring, the bearing ramp having a first portion, a secondportion, and a detent finger disposed between and separating the firstportion from the second portion, the detent finger includes a first rampthat extends from a tip region of the detent finger towards the firstportion and a second ramp that extends from the tip region of the detentfinger towards the second portion.
 2. The park shift assist mechanism ofclaim 1, wherein the tip region of the detent finger has a tip regionradius of curvature and the roller ball has a roller ball radius ofcurvature that is less than the tip region radius of curvature.
 3. Thepark shift assist mechanism of claim 2, wherein the first portioncorresponds to the park position of the gear shift lever and the secondportion corresponds to the reverse position of the gear shift lever. 4.The park shift assist mechanism of claim 3, wherein the detent finger ispositioned on the bearing ramp at a location corresponding to a positionof the gear shift lever between the reverse position and the parkposition.
 5. The park shift assist mechanism of claim 4, wherein whenthe gear shift lever is positioned between the park position and thereverse position, the roller ball is disposed on the detent finger andthe spring applies a pressing force to the roller ball to urge theroller ball against at least one of the tip region, the first ramp, andthe second ramp of the detent finger.
 6. The park shift assist mechanismof claim 5, wherein in response to the roller ball being urged againstthe tip region and the first ramp, the gear shift lever is positivelypositioned towards the park position.
 7. The park shift assist mechanismof claim 5, wherein in response to the roller ball being urged againstthe tip region and the second ramp, the gear shift lever is positivelypositioned towards the reverse position.
 8. A park shift assistmechanism, comprising: a gear clevis that is operably connected to agear shift lever that is movable between a park position and a reverseposition, the gear clevis having a bearing ramp that includes a firstportion, a second portion, and a detent finger separating the firstportion from the second portion, the detent finger having a tip regionwith a tip region radius of curvature; and a spring loaded bearingfollower including: a spring, and a roller ball biased towards thebearing ramp by the spring, the roller ball having a roller ball radiusof curvature that is less than the tip region radius of curvature, whenthe gear shift lever is positioned between the park position and thereverse position, the roller ball is disposed on the detent finger andthe spring applies a pressing force to the roller ball to urge theroller ball against the tip region of the detent finger to positivelyposition the gear shift lever towards at least one of the park positionand the reverse position.